Re: [PATCH v2 3/5] arm64: dts: allwinner: a523: Add EMAC0 ethernet MAC

Linus Walleij
2025-05-09T11:50:31Z

On Fri, Apr 25, 2025 at 5:05 PM Andre Przywara <andre.przywara@arm.com> wrote:
> On Fri, 25 Apr 2025 22:35:59 +0800
> Chen-Yu Tsai <wens@csie.org> wrote:
>
> adding LinusW for a more generic pinctrl question ...

OK!

> > There isn't any assumption, as in we were fine with either the reset
> > default or whatever the bootloader left it in. However in projects at
> > work I learned that it's better to have explicit settings despite
> > working defaults.
>
> I totally agree, but my point was that this applies basically to every
> pinctrl user. I usually think of the bias settings as "do we need
> pull-ups or pull-downs", and if nothing is specified, I somewhat assume
> bias-disable.
>
> So I am fine with this being added here, but was wondering if we should
> look at a more generic solution.
>
> Linus: is bias-disable assumed to be the default, that pinctrl drivers
> should set in absence of explicit properties? Or is this "whatever is in
> the registers at boot" the default we have to live with?

We have never hammered down the semantics of that, so it's a bit
up to the specific driver how they implement it (yeah a grey area...)

There are many drivers that are carful to not touch register boot
values but others who set them to some default, and people
have different opinions on that.

Yours,
Linus Walleij